Untargeted Analysis Resource of the Minnesota CHEAR Exposure Assessment Hub SUMMARY: The Untargeted Analysis Resource in the Minnesota CHEAR Exposure Assessment Hub will simultaneously measure large sets of analytes (hundreds to thousands) in the biological samples from child health studies, and conduct hypothesis-free analysis to identity the association between exposure and biological response. The Resource has highly experienced investigators and established platform to conduct untargeted metabolomics and data analysis. The functions of the Resource, which are complementary to the functions of the Targeted Analysis Resources and the Biological Response Indicators Resource in the Hub, are defined by three specific aims on data acquisition, interpretation and disposition. In Aim 1, this resource will provide a reliable platform for conducting timely and comprehensive metabolite analyses of biological samples. Standard operating procedures (SOPs) of metabolite extraction and chemical derivatization have been established for preparing biological samples for mass spectrometry-based metabolomics. Chromatographic and spectrometric conditions for separating and detecting individual groups of metabolites have also been optimized for a broad-spectrum examination of both endogenous and exogenous metabolites in biological samples. In Aim 2, this resource will conduct comparative analysis of metabolomic data based on the classification or stratification information on samples. Metabolites of interest will be characterized by structural analysis and bioinformatics. In Aim 3, this resource will guide research efforts on new exposure markers in the development core and to deposit data in the data repository, analysis and science center. Overall, the Untargeted Analysis Resource will generate novel insights on exposure, exposure-induced metabolic changes, and the underlying biochemical mechanisms. These new knowledge could be used to explain the phenotypes of exposed children or lead to the development of new targeted analysis on metabolites and biological responses.